JP2512013B2 - Board static elimination method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of removing static electricity from a substrate, for example, a spacer for forming a gap of a liquid crystal display panel, which sprays fine powder susceptible to static electricity.

2. Description of the Related Art Conventionally, for example, a substrate in which a spacer of a liquid crystal display panel is dispersed has a transparent electrode, a protective film, an alignment film, etc. formed on a glass substrate, and a rubbing cloth made of nylon or the like is brought into contact with the substrate for alignment treatment. What is done is used. This substrate is charged with static electricity, and when the spacer is dispersed in this state, it repels when the spacer and the substrate have the same potential, and adsorbs when the spacer and the substrate have the opposite potential. Due to this, the dispersion density of the spacers on the substrate differs, and a cap defect occurs. In order to prevent these, there is a method described in (Japanese Patent Application No. 62-64553), in which spacers are sprinkled after the substrate is neutralized by a voltage application type static eliminator.

Problems to be Solved by the Invention Such a conventional static elimination method has the following problems. Spacers made of spherical or columnar glass or resin of several μm are affected by slight static electricity.
On the other hand, when static electricity is removed with a voltage application type static eliminator, those with ion balance adjustment generally have low static elimination ability,
The amount of charge on the substrate after static elimination varies and the static elimination time is long, resulting in poor mass production efficiency. Further, the one without ion balance adjustment has a high static elimination ability, but the ion balance is different, and the substrate is reversely charged to either one. Further, regardless of whether or not the ion balance is adjusted, the voltage application type static eliminator has a problem that dust and the like are attached to the electrodes and the static eliminability changes with the use time, resulting in a different ion balance. Furthermore, if the initial charge amount of the substrate is different by several KV due to variations in the substrate and orientation treatment, etc., when the same static eliminator is used for static charge removal for the same time, the static charge on the substrate after static charge will be different and a constant charge will be obtained. It doesn't amount. As a result, the spacer dispersion density of the substrate varies. In view of such a point, the present invention provides a method of removing static electricity from a substrate by a simple method in which the charge amount of the substrate after static elimination is stabilized and variation is reduced.

Means for Solving the Problems In order to solve the above problems, the present invention places a substrate on a tray, provides switching means for grounding and insulating this tray, and operates the static eliminator at least twice to Insulate the tray during the first operation, ground the tray after stopping the first operation, and then perform the second operation.

Action The present invention has the above-described configuration, insulates the tray, operates the static eliminator, and neutralizes the substrate and the tray to the same potential,
By grounding the tray, the potential of the substrate and that of the tray cancel each other and the charge amount of the substrate becomes near OV. In this state, the static eliminator is actuated again to neutralize the charge of the substrate having a charge amount near OV, thereby enabling stable static neutralization.

Embodiment An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, a substrate 1 is placed on a tray 2 made of a conductor such as metal. Changeover switch 3 for tray 2
Is connected and can be grounded or insulated to the ground. Static elimination bars 4 and 5 are installed on the substrate 1 at positions separated by a predetermined distance (about 4 cm), and are connected to high-voltage power sources 6 and 7, respectively. The static eliminator comprises one static eliminator bar 4 and one high-voltage power source 6, and each pair is called a static eliminator. Next, a case where the substrate 1 is discharged with such a configuration will be described. For example, in the case of handling a liquid crystal substrate, in the case where the surface of the substrate 1 is rubbed and subjected to an alignment treatment, the surface of the substrate 1 is charged to several KV. The substrate 1 is placed on the tray 2 and the static eliminator is operated. At this time, the changeover switch 3 is open and the tray 2 is in a state of being insulated from the ground. The static electricity is removed from the substrate 1 and the tray 2 in a predetermined time after the static elimination is started, and the value of several KV becomes a value of several 10V to several 100V. Although this value varies depending on variations in the static eliminator and changes over time, the charge amounts of the substrate 1 and the tray 2 are equal (FIG. 2). Next, when the operation of the static eliminator is stopped and the tray 2 is grounded by the changeover switch 3, the charge amount of the substrate 1 becomes 0 to several tens of volts. This is effective only when the insulated tray 2 and the substrate 1 are charged by the static eliminator (the third charge).
Figure). In this state, the spacer material may be scattered on the substrate 1, but conversely, the substrate 1 may be provided with an electric potential opposite to the electric potential of the spacer material, and again in order to efficiently attach (pull) the scattered spacer material. By operating the static eliminator to charge the static eliminator, it is possible to obtain a stable charge amount according to the capability of the static eliminator. This is the case where the initial charge amount of the substrate 1 has a variation of several KV at the first charge removal, but the charge amount of the substrate 1 has a small variation of 0 to several tens V at the second charge removal. Depends on. In this way, the substrate 1 is destaticized.
In addition, when the spacer material is sprayed, the spacer material can obtain a stable dispersion density without variation in a large number of substrates and does not cause a gap defect. Next, when the spacer material has either of the electric potentials of and, the electric potential of the substrate 1 must be 0. In this case, claims 2 to 4 will be described. In the second term, as a characteristic of the static eliminator, the farther the electrode is from the poled object, the lower the static elimination ability is, but the ion balance of the static eliminator is mixed and neutralized. Therefore, as shown in FIG. 4, in the first static elimination, the static elimination bar 4 is brought close to the substrate 1 in order to charge the substrate 1 by several KV, and in the second static elimination,
Since the charge of several tens of volts of the substrate 1 is only brought to near 0V, the charge removal capability may be low, and the charge removal amount of the substrate 1 can be made close to 0 by performing charge removal at a position away from the substrate 1. it can. Next, as to the third term, as shown in FIG. 5, a conductive net 8 is attached between the charge eliminating bar 4 and the substrate 1. The mesh 8 is made of meshes having different porosities, and can be moved on the substrate 1 by the rolls 9 and 10 at both ends. Again net 8
Is grounded. By doing so, when the ions emitted from the static elimination bar 4 are not uniform, after passing through the net 4, the number of ions decreases and the static elimination capability decreases, but the ion balance becomes uniform. This equalization differs depending on the open area ratio of the mesh, and can be made uniform by selecting the open area ratio according to the capability of the static eliminator. Therefore, the charge amount of the substrate 1 can be close to 0 by using the non-meshed portion 11 during the first charge removal and using the mesh during the second operation.

EFFECTS OF THE INVENTION As described above, according to the present invention, even if the charged substrate is deviated in the performance of the static eliminator or the ion balance due to aging, stable static neutralization can be performed with a simple structure, and the liquid crystal panel It is possible to eliminate gap defects due to static electricity in the spacer spraying work, etc.

[Brief description of drawings]

FIG. 1 is a perspective view showing a method of static elimination of a substrate in one embodiment of the present invention, FIG. 2 is a side view showing a substrate potential before static elimination by the method, and FIG. 3 is a substrate after static elimination by the method. Side views showing the potential, FIGS. 4 and 5 are perspective views of another embodiment of the method. 1 ... Board, 2 ... Tray, 3 ... Changeover switch, 4,
5 ... Static elimination bar.

Claims (3)

(57) [Claims] 1. A static elimination method for a charged substrate, comprising a tray on which the substrate is placed, a switching means for grounding and insulating the tray, and at least one static eliminator at a position at a predetermined distance from the substrate. Is provided, the static eliminator is operated at least twice, the tray is insulated during the first operation, the tray is grounded after the first operation is stopped, and then the second operation is performed. 2. The static elimination is performed by changing the distance between the static eliminator and the substrate between the first operation and the second operation.
A method for eliminating static electricity from a substrate according to the item. 3. The method for static elimination of a substrate according to claim 1, wherein a conductor is provided in the vicinity of the static eliminator, and the static elimination ability is varied by moving the conductor.